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Author Topic: Can I use this relay to control 12 V DC?  (Read 1000 times)
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universe
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Can I use this relay to turn on or off 12V DC electronic equipment?
http://www.dfrobot.com/wiki/index.php?title=Relay_Module_%28Arduino_Compatible%29_%28SKU:_DFR0017%29
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Can I use this relay to turn on or off 12V DC electronic equipment?
http://www.dfrobot.com/wiki/index.php?title=Relay_Module_%28Arduino_Compatible%29_%28SKU:_DFR0017%29

Yes, as long as the amount of 12V current you are switching on and off don't exceed the maximum current rating of the contacts on the relay.

Lefty

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The dfrobot page has a link to the data sheet for the relay which states that it is rated up to 5A at 24V DC.

EDIT: whoops, it links to the wrong datasheet smiley-razz. Here's the correct datasheet.
« Last Edit: January 18, 2013, 01:56:13 pm by Chagrin » Logged

universe
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Do you know what is the maximum current rating of the relay for 12V DC? I am not sure reading the datasheet.
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I am trying to turn lock and unlocked this solenoid door:
http://www.tokopedia.com/awgmarket/solenoid-door-lock-12v
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@lefty..... what might it be about that relay that would cause it to have different current ratings on the NO vs NC connections?

And is that a common thing in relays in general?


* relay.JPG (48.77 KB, 569x425 - viewed 28 times.)
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@lefty..... what might it be about that relay that would cause it to have different current ratings on the NO vs NC connections?

And is that a common thing in relays in general?

You know I saw that rating and was somewhat surprised as I've never seen that kind of rating ever before. I have seen a given relay have lower current rating for switching DC then AC on the same physical relay as breaking AC current gets the benefits of the AC voltage doing zero crossings, where as DC always creates higher arcing on the contacts for the same current value. So maybe a datasheet error really meaning 10 amps max if AC or 5 amps if DC? Either way one should most likely limit DC current switching to 5 amps max for that relay unless better information is forthcoming from the manufacture.

Lefty
« Last Edit: January 18, 2013, 02:17:29 pm by retrolefty » Logged

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But when I connect to that solenoid lock door, and following the code
Code:
//Arduino Sample Code
//www.DFRobot.com
//Last modified on 14th March 2012 by HJS
//This code has been updated to work with the sample code provided in the Wiki
 
int Relay = 3;
 
void setup()
{
  pinMode(13, OUTPUT);         //Set Pin13 as output
  digitalWrite(13, HIGH);     //Set Pin13 High
  pinMode(Relay, OUTPUT);     //Set Pin3 as output
}
void loop()
{
          digitalWrite(Relay, HIGH);   //Turn off relay
          delay(2000);
          digitalWrite(Relay, LOW);    //Turn on relay
          delay(2000);
}

from http://www.dfrobot.com/wiki/index.php?title=Relay_Module_%28Arduino_Compatible%29_%28SKU:_DFR0017%29  <-- here using led

but the solenoid doesn't show any changes. Is it possibly means that the solenoid door lock require more than 5 A?
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but the solenoid doesn't show any changes.
Do you here the relay click?

Quote
Is it possibly means that the solenoid door lock require more than 5 A?
If you put more current through a relay than its ratings, first the life is shortened, and then the contacts weld together. So in either event your solenoid should move.
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but the solenoid doesn't show any changes. Is it possibly means that the solenoid door lock require more than 5 A?

That sounds to me like a wiring problem on the output contacts side of your relay/solenoid/power source setup. Or maybe whatever door solenoid voltage source you are using is not up to the task? Can you post a drawing of your output wiring?

Lefty
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universe
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Yes I do hear a click!
what does it mean? my english is not really good.
Quote
If you put more current through a relay than its ratings, first the life is shortened, and then the contacts weld together. So in either event your solenoid should move.
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Yes I do hear a click!
what does it mean?
It means the relay is working and the fact that you solenoid does not move is down to the fact that either you have not wired it up correctly or your power supply cannot supply enough current.
Measure the voltage on your power supply and see if it dips when the relay kicks in.
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@lefty..... what might it be about that relay that would cause it to have different current ratings on the NO vs NC connections?

And is that a common thing in relays in general?

It's not uncommon, especially in the world of automotive relays. The standard Bosch/Tyco relay can carry 40A on the NO and 30A on the NC. In general the idea is that the NO item is the high power contact you want to switch on and off. So in general if there is a rating difference the NO is usually the higher of the two.
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Need help, here is my circuitry, it works on led but not on solenoid:



is there any wrong?
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additional, the powerjack could supply till 2A
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